<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category  Zend
 * @package   Zend_TimeSync
 * @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd     New BSD License
 * @version   $Id: Protocol.php 16209 2009-06-21 19:20:34Z thomas $
 */

/**
 * Abstract class definition for all timeserver protocols
 *
 * @category  Zend
 * @package   Zend_TimeSync
 * @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license   http://framework.zend.com/license/new-bsd     New BSD License
 */
abstract class Zend_TimeSync_Protocol
{
	/**
	 * Holds the current socket connection
	 *
	 * @var array
	 */
	protected $_socket;

	/**
	 * Exceptions that might have occured
	 *
	 * @var array
	 */
	protected $_exceptions;

	/**
	 * Hostname for timeserver
	 *
	 * @var string
	 */
	protected $_timeserver;

	/**
	 * Holds information passed/returned from timeserver
	 *
	 * @var array
	 */
	protected $_info = array();

	/**
	 * Abstract method that prepares the data to send to the timeserver
	 *
	 * @return mixed
	 */
	abstract protected function _prepare();

	/**
	 * Abstract method that reads the data returned from the timeserver
	 *
	 * @return mixed
	 */
	abstract protected function _read();

	/**
	 * Abstract method that writes data to to the timeserver
	 *
	 * @param  string $data Data to write
	 * @return void
	 */
	abstract protected function _write($data);

	/**
	 * Abstract method that extracts the binary data returned from the timeserver
	 *
	 * @param  string|array $data Data returned from the timeserver
	 * @return integer
	 */
	abstract protected function _extract($data);

	/**
	 * Connect to the specified timeserver.
	 *
	 * @return void
	 * @throws Zend_TimeSync_Exception When the connection failed
	 */
	protected function _connect()
	{
		$socket = @fsockopen($this->_timeserver, $this->_port, $errno, $errstr,
		Zend_TimeSync::$options['timeout']);
		if ($socket === false) {
			throw new Zend_TimeSync_Exception('could not connect to ' .
                "'$this->_timeserver' on port '$this->_port', reason: '$errstr'");
		}

		$this->_socket = $socket;
	}

	/**
	 * Disconnects from the peer, closes the socket.
	 *
	 * @return void
	 */
	protected function _disconnect()
	{
		@fclose($this->_socket);
		$this->_socket = null;
	}

	/**
	 * Return information sent/returned from the timeserver
	 *
	 * @return  array
	 */
	public function getInfo()
	{
		if (empty($this->_info) === true) {
			$this->_write($this->_prepare());
			$timestamp = $this->_extract($this->_read());
		}

		return $this->_info;
	}

	/**
	 * Query this timeserver without using the fallback mechanism
	 *
	 * @param  string|Zend_Locale $locale (Optional) Locale
	 * @return Zend_Date
	 */
	public function getDate($locale = null)
	{
		$this->_write($this->_prepare());
		$timestamp = $this->_extract($this->_read());

		$date = new Zend_Date($this, null, $locale);
		return $date;
	}
}
